Means fob transferring impressions



March 13,1934. 7 PlTMAN 1,951,203

MEANS FOR TRANSFERRING IMPRESSIONS 0F FINGERPRINTS *Filed July 18, 1928 A TTOPNEV Patented Mar. 13, 1934 UNITED STATES MEANS FOR TRANSFEBRING IIHPRESSIONS OF FINGERPRINTS Herman E. Pitman, St. Louis, Mo., assignor of one-half to Sam Silk, St. Louis, Mo.

Application July 18, 1928, Serial No. 293352 3 Claims. (on. rid-2s) This invention relates generally to a means for transferring impressions of finger prints and more specifically to an improved method and means whereby an impression made by a human finger on a wall of a building, or other immovable object, may be transferred to a sheet of material which is capable of being conveyed to a place where photographic reproductions of the finger print may be made.

It is very common knowledge that the use of finger prints has attained a place of very great importance'in the detection and prosecution of criminals, but prior to this invention, the value of finger prints for these purposes has frequently been entirely and completely lost due to the fact that said finger prints were produced at places, where, because of the a'bsence of suflicient light, and for other reasons, it has been impossible to photograph them and in this manner perpetuate same. It has frequently happened, for instance, that a criminal forcing his way into a dwelling left a finger print on a wall in a relatively dark part of a room. The persons attempting to solve the crime would be able to find the finger print but because of the absence of sufiicient light, same could not be photographed and hence no means were available for perpetuating the finger print so same could be used at the trial of the accused.

In view of the foregoing, I have devised the means disclosed herein which briefly stated, comprises dusting the finger print with aluminum powder so that all of the lines which characterize same are clearly apparent. A sheet of prepared adhesive material is then applied to the powdered finger print and when the same is removed therefrom, the aluminum powder will adhere to said sheet in the formation which said powder assumed on the original fingerprint. The impression of the finger print in powder on the adhesive sheet is then covered by a sheet of transparent material and the unit comprising the sheet of material, the powder, and the sheet of transparent material may be conveyed to a suitable place where same may be photographed.

In the drawing which is intended'to illustrate my improved method as well as the means for carrying said method out,

Fig. 1 illustrates a finger print produced on a section of a wall or other immovable object.

Fig. 2 shows a piece ofmy improved adhesive material applied to the portion of the object on which the finger print appears.

Fig. 3 shows the piece of adhesive material in perspective after same has been removed from the object on which the finger print was produced.

Fig. 4 illustrates in perspective a piece of my improved adhesive material after a finger print has been applied thereto, and the transparent sheet has been arranged thereon, portions of said sheet being shown in section.

To describe first, the means by which my im= proved method is carried out, A designates a section of the sheet of material to which an impression of a finger print may be transferred for photographic or" other purposes. The sheet of material of which the sections A shown in Figs. 2, 3 and 4 are fragments, comprises a layer of material B providing a backing for the sheet, said material preferably being fabric of the type 70 known as sheeting. Arranged on one face of the layer of material B is a layer of gum C, said layer of gum C preferably being coextensive of the layer of backing material and being of an adhesive 7 nature.

I have found that an ideal compound for arrangement on the backing material B of the sheet A to provide the layer of gum C comprises ingredients enumerated below, however, I do not limit myself to this precise composition as others may be found which will function satisfactorily:

34 lb. batch Pounds Latex first crepe rubber 25 Guayule rubber 6 Carbon black Cumar rubber, soft 1 Cotton seed oil i In producing the sheet A the ingredients of which the compound is comprised is mixed in a rubber mixer, after which the backing material B is skim-coated therewith with the aid of a calender.

D designates a layer of transparent material such as thin celluloid, said layer of material being arranged to entirely cover the layer of gum C as shown in Fig. 4. The layer of transparent material D is rigidly fixed to the sheet A by the gum C because of the adhesive nature thereof.

In following out my improved method of transferring finger prints, the finger print to be transferred is located and said finger print is dusted over lightly with a powder which is preferably of light color. I have found that a powder which functions in a highly eflicient manner for my purpose, is aluminum powder, but it is obvious that other powders may be employed. The powder referred to is applied to the finger print with the aid of an atomizer or similar distributing device and when said powder is so applied to the finger print all of the lines which characterize same will be caused to stand out, the powder gathering on said lines so that the prominence thereof is greatly accentuated. After the finger print has had the powder appliedjhereto, in the manner described, the excess powder is brushed lightly from said finger print and from around same, with the aid of a very soft brush.

After the finger print has been powdered, as described, the next step of the method is to cut a piece of the sheet A of a size sufiicient to receive the impression of ,the finger print, and from this piece of the sheet the layer of transparent material is removed. The piece of sheet A is then applied to the finger print with the gummed surface of said piece of sheet in contact with said finger print, and said piece of sheet is pressed firmly in contact with the article on which the finger print appears. The next step of the method is to remove the piece of sheet from the article on which the finger print appears and when such removal takes place the powder which was applied to the finger print will adhere to the adhesive covered surface of the piece of sheet A in the formation in which it appeared on the finger print, hence the finger print will be reproduced in powder on the adhesive covered face of the piece of sheet A. The layer of transparent material which was removed from the sheet A before same was applied to the finger print is then reapplied to the adhesive covered surface of A, thereby covering the powder in which the finger print is reproduced so that said powder may not be subsequently disturbed. The unit comprising the sheet A and layer of transparent material may then be trans mitted or conveyed to the place where it is to be preserved or where photographic reproductions are to be made thereof, and because the powder clearly defines the lines which characterize the finger print the piece of sheet A to which a finger print has been transferred, or a photographic reproduction thereof, will clearly show the various lines of the original finger print.

I claim:

1. A device for transferring finger prints from articles on which same are produced comprising a sheet of material, said sheet of material comprising a layer of backing material, and a layer of adhesive material, including amounts of rubber, and cotton seed oil, arranged on said backing material.

2 A device for transferring finger prints from articles on which same are produced comprising a sheet of material, said sheet of material comprising a layer of backing material, and a layer of adhesive material, including amounts of rubber, carbon black, and cotton seed oil, arranged on said backing material.

3. A device for transferring finger prints from articles on which same are produced comprising a sheet of material, said sheet of material comprising a layer of backing material, and a layer of adhesive material, arranged on said backing material, said adhesive material including amounts of latex first crepe rubber, guayule rubber, carbon black, cumar rubber soft, and cotton seed oil.

HERMAN E. PITMAN. 

